Metal detergents belong to an indispensable class of additives in lubricant oil. On the one hand, as surfactants, metal detergents inhibit the severe pollution damage caused by fuels and lubricant oil in internal-combustion engines by means of their solubilization, peptization or detergent dispersing effects; and on the other hand, metal detergents can provide alkaline storage, effectively neutralize harmful inorganic and organic acids inevitably generated from fuels and lubricant oil under operating conditions, and consequently, achieve the goals of slowing down oxidation and deterioration of oil, reducing abrasion and wearing of engines, and prolonging working life of oil and engines.
Sulfurized calcium alkyl phenolate is an important metal detergent, which has excellent detergency under high temperature and acid neutralizing capacity, and meanwhile, has good resistance to oxidation and corrosion. Alkyl phenol is an important raw material for producing sulfurized calcium alkyl phenolate. Currently, the contents of free alkyl phenol in the products from different domestic and foreign manufacturers are 5-10 wt %. Residual free alkyl phenol in products may have side effects on the detergency and resistance to oxidation of the products. Meanwhile, the environmental problems generated therefrom can not be neglected: said substance is not easily degraded under the environments of soil, water area, etc., and can be accumulated in organisms, produce obvious estrogen effect, cause varying degrees of endocrine toxicity, reproductive toxicity, neurotoxicity, immunotoxicity, genetic toxicity or the like on organisms, and cause severe threats to the entire ecosystem.